Bacteria of the genus Salmonella are pathogens of significant concern in worldwide health. Salmonella species are among the most significant food-borne pathogens affecting both agriculture and humans, causing morbidity and mortality across the globe. In humans, the elderly, infants, and those with impaired immune systems are more likely to develop severe salmonellosis. In severe cases, the Salmonella infection may spread from the intestines to the blood stream and then to other body sites, and such infection often proves fatal if not treated with the appropriate antibiotics. Indeed, Salmonella is the leading cause of death from food-borne illness in the United States. Although in the United States most cases of salmonellosis are self-limiting, some people afflicted with salmonellosis later experience reactive arthritis, which can have long-lasting, disabling effects. Another form of Salmonella disease, called invasive non-typhoidal salmonellosis (iNTS), is emerging, especially in Africa where the disease is associated with malaria infection in children and HIV infection in adults. Typhimurium and Enteritidis serovars are the most medically significant serovars in the United States, and the most common serovars associated with iNTS.
In addition, Salmonella serovars have been implicated in a spectrum of other diseases, including enteric or typhoid fever (primarily from S. typhi and S. paratyphi), bacteremia, endovascular infections, focal infections (e.g., osteomyelitis), and enterocolitis (typically from S. typhimurium, S. enteritidis, and S. heidelberg). Currently, there are no human vaccines for the non-typhoidal Salmonella serovars. Antibiotics are not recommended for uncomplicated cases of Salmonella-mediated gastroenteritis, but are used to treat the very young or elderly, or when there are complications or invasive disease. Multiple drug resistance is prevalent and increasing, however, hence novel therapeutic approaches are needed for preventing or treating non-typhoidal salmonellosis. 
The species S. enterica contains over 99% of the serovars that are capable of infecting cold and warm blooded animals, as well as humans. Indeed, more than 2500 serovars of S. enterica have been identified. S. enterica subspecies enterica includes typhoidal serovars that cause typhoid fever, and non-typhoidal serovars that cause gastroenteritis. These serovars can infect a remarkably broad range of host species, infecting a large number of different animals and even plants. In humans, S. enterica infection is usually contracted after eating, for example, contaminated or infected eggs, egg products, or milk that was not prepared, handled, or refrigerated properly; meat if it was prepared incorrectly or was contaminated with Salmonella after preparation; or contaminated fruits or vegetables. The Centers for Disease and Control and Prevention estimates that in the United States alone there are about 1.4 million cases per year of non-typhoidal salmonellosis. Because Salmonella-tainted foods often have no unusual look or smell, it is imperative that food sources can be tested efficiently for the presence of Salmonella. Moreover, accurate diagnosis of Salmonella infection that allows for treatment options, i.e., antibiotic therapy, is an important healthcare goal.